The polycarbonates are a well known polymer family useful in applications wherein toughness, impact resistance, temperature resistance and electrical properties, among others, are significant. It is also a well known fact that the glassy polymers such as polycarbonates, can be readily reinforced so as to obtain a higher modulus and tensile strength among other properties with reinforcing materials such as glass, ceramics, asbestos, silica, mica, carbon/graphite, and the like. The forms which these reinforcing materials can take include fibers, mats, flakes, whiskers, and in general any form which provides reinforcement to the polycarbonate. However, when the polycarbonates are reinforced with these materials, generally certain property advantages are substantially lessened. Among these and perhaps the most significant is the impact strength and elongation of the polycarbonate. It is well known that the addition of glass fibers to polycarbonates increases the modulus and tensile strength of the polycarbonate composition significantly while concurrently sharply reducing the impact strength of the polycarbonate. In some instances the impact strength of the composition can be retained to a great extent by adding a third compatibilizing component. For example in U.S. Pat. No. 3,640,943, Bostick, et al, issued to General Electric Company, the addition of a relatively small quantity of a polycarbonate polydimethylsiloxane block copolymer to a composition of polycarbonate and glass fiber, or coating the glass fibers with the polycarbonate polysiloxane block copolymer and then adding substantial quantities of polycarbonate brings about a final composition with significant levels of impact resistance.
However, there still remains a need for preparing reinforced polycarbonate or polycarbonate like compositions which maintain a significant quantity of the polycarbonate like characteristics to a substantial extent.
It has now been found that a specific type of polycarbonate copolymer resin can be reinforced with a certain kind of reinforcing material and still retain virtually all of the impact resistance known for the components of the composite system.